Current plans for supportive care research call for activity in four separate areas: 1) Epidemiology of infectious disease; 2) Early diagnosis of pulmonary and fungal infection; 3) Studies of therapeutic granulocytes and modulations of antibiotic and antifungal therapy; and 4) Prophylaxis of infection by the use of prophylactic granulocytes and by the use of barrier reverse isolation and/or oral non-absorbable antibiotics. We are particularly stressing the application of computer methodology to the prospective acquisition and storage of infection incidence and mortality data; the use of transbronchoscopic biopsy for the diagnosis of pulmonary infiltrates of unknown etiology compared to conventional methods as well as surgical lung biopsy; a prospective randomized evaluation of granulocytes as prophylaxis and as therapy of severe infection and the institution of reverse isolation and endogenous flora suppression with oral non-absorbable antibiotics as a method of preventing infection, and as an approximation of the germ-free animal to assess the relationship of the presence of GI flora, with the pharmacokinetics of anti-cancer agents.